HT4100 4.1, 4.5, 4.9 Discussion, No heat at 90 degrees on climate control 93 caddy in Cadillac Engine Technical Discussion; Car has no heat with climate control temp sent at 90 cars runs great no heat blows cold air....

Re: No heat at 90 degrees on climate control 93 caddy

Originally Posted by mike93

Car has no heat with climate control temp sent at 90 cars runs great no heat blows cold air.

Remove the glove box @ 5 screws. You'll find an electric motor with a rod attached to it close to the back of the firewall. This part controls a door that allows hot from the heater core or cold air from the evaporator to enter the car.

Check and see if the electric motor is moving the rod and door it is attached to by adjusting the temperature up and down on the climatic control panel.

If the rod is all the way to the left it is in the cold position and all the way to the right is hot. You can also snap the rod out of the electric motor to operate the temperature control door manually for verification.

If the motor is not moving the rod it could be a bad electric motor (check for power to the motor first) or one of the controllers to the climatic control system.

Be careful with the air bag system. You will want to pull the aur bag fuse

Re: No heat at 90 degrees on climate control 93 caddy

I just had the same problem with my 95 Deville. I had the cooling system flushed and a new thermostat. It turned out that the heater core was plugged and couldn't be flushed. The flushing, new thermostat and fresh coolant along with a new heater core cost me $258. I was happy with that. It is getting cold in Indiana.